The dial design has just one objective; maximum legibility, even deep in the ocean where sunlight does not penetrate. The hour markers are large, so as to allow the maximum surface area and depth for Seiko’s Lumibrite coating. The hands, too, are wide and easy to read.
Unique design of the bezel enhance the operability

The deep grooves in the bezel are designed for easy operation, even when diving gloves are worn.
FUNCTION
Water resistance : 200m Diver
The watch is designed and manufactured to withstand up to 200m going under the water, and is suitable for wearing while scuba diving.
Screw-down crown
The crown has screw-down protection to prevent it from being pulled out by any accidental operation as the water resistance function is secured only when the crown is at its normal position.
TECHNOLOGY
The unidirectional rotating bezel
The precise and secure operation of the uni-directional bezel prevent accidental rotation, so that the time measured is never shorter than the actual elapsed time.